Abstract
The valve is particularly adapted for respiratory work. It consists of a vertical 9 cm. length of 22 mm. glass tubing; the tube projects 1.5 cm. through the center of an inverted No. 13 rubber stopper. The upper surface of the stopper has a layer of canton flannel. A light celluloid cup, in cross section a parabola, and 4.5 cm. in diameter, covers the open tube and rests on the flannel. Projecting downward from the center of the cup is a light rod of pyrex glass, which passes through 2 gold bearings. A check on the end of the rod permits it to move 1.5 cm. vertically. The stopper fits into an inverted glass bell 7 cm. high. At the top, the bell is continuous with a 5 cm. length of 22 mm. glass tubing. A layer of mercury 0.5 cm. deep is placed on the flannel surface. The celluloid cup floats on the mercury. When suction is applied at the upper tube, the cup rises vertically from the mercury and permits the incoming air to pass; when pressure is applied the cup is forced down to the flannel surface and the mercury seals the joint. When used as an expiratory valve, the condensed water is drained off by a small wick which extends through the stopper at the periphery.
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